Core–Shell Pd@M (M=Ni, Cu, Co) Nanoparticles/Graphene Ensembles with High Mass Electrocatalytic Activity Toward the Oxygen Reduction Reaction

Abstract

Herein, it is demonstrated that pyrene butyric acid (PBA)-stabilized metaln anoparticles with core-shell morphology, Pd@M NPs (M = Ni, Cu, Co), non-covalently supported on graphene (G) sheets, are more active towards oxygen electroreduction in alkaline environments than the benchmark Pd/C catalyst, albeit with a7 0% lower preciousm etal loading. The PBA-stabilized Pd@M NPs (M = Ni, Cu, Co)/G ensemblesw ere prepared by employing as imple modified polyol method andg alvanic replacementa nd thoroughly characterizedw ith advanced microscopy imaging and complementary spectroscopic techniques.E lectrochemical studies revealed that Pd@Ni NPs /G presents the optimump erformance, exhibiting a3 0mVm ore positive onset potential and 3.2 times greater mass activityo ver Pd/C. Moreover, chronoamperometric assays showedt he minimum activity loss for Pd@Ni NPs /G, not only among its core-shell counterparts buti mportantlyw hen compared with the benchmark catalyst.T he excellent performance of Pd@Ni NPs /G was attributed to the (a) presence of PBA as stabilizer,( b) uniform Pd@Ni NPs dispersion onto the graphene sheets, (c) efficient intra-ensemble interactions between the two species, (d) existence of the core-shell structure for Pd@Ni NPs ,a nd (e) stability of the Ni core metal under the reactionc onditions. Last, the oxygen reduction on Pd@Ni NPs /graphene occurs by the direct four-electron reduction pathway,s howinggreat potentialfor use in energy related applications.Supporting information and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

Surface Modification for Promoting Durable, Efficient, and Selective Electrocatalysts

“…Many different functionalized nanostructures with different shapes have been described, including Janus nanoparticles, nanodendrites, alloys and core‐shell nanoparticles . Functionalization of PtNi alloys through simple adsorption of cyanides has a positive impact on the onset potential (E onset ) and half‐wave potential (E 1/2 ) of the catalyst compared to commercial Pt black, but especially enhances their methanol tolerance.…”

“…These nanocatalysts also show enhanced HER activity compared with PdNi catalysts without PEI. PdNi core‐shell nanoparticles stabilized by pyrenebutyric acid were deposited on graphene materials . These materials exhibit improved ORR performance in alkaline media compared to commercial Pd/C, with a 30 mV‐more positive E onset potential and a 3.2‐fold mass activity increase.…”

“…These materials exhibit improved ORR performance in alkaline media compared to commercial Pd/C, with a 30 mV‐more positive E onset potential and a 3.2‐fold mass activity increase. The ORR mechanism was suggested to follow a direct four‐electron pathway …”

Carbon Nanohorn-Based Electrocatalysts for Energy Conversion

“…Without a doubt, the investigation and exploration of novel, less expensive, and abundant electrocatalysts for the ORR is of paramount importance. Recent research has focused on highly active catalysts driving the 4e − ORR, including Pt alloys [ 48 ], core-shell nanostructures [ 50 ], transition metal oxides [ 51 ], and chalcogenides [ 52 ], and carbon-based non-noble catalysts [ 53 , 54 ]. Carbon-based materials, such as graphene, doped graphene, and CNTs have been studied as conductive supports in ORR due to their excellent conductivity and high surface area [ 52 , 53 , 54 , 55 ].…”

A Composite Bifunctional Oxygen Electrocatalyst for High‐Performance Rechargeable Zinc–Air Batteries

“…The composite strategy for bifunctionalo xygen electrocatalysis has been demonstrated to be effective in many cases. [46][47][48][49][50][51][52][53][54] For instance, Chen et al reported ac omposite of manganese dioxide andn itrogen-doped carbon nanotubes with high bifunctional electrocatalytic reactivity. [55] The composite of NiFe layered doubleh ydroxides with Co, Nc o-doped carbon nanoframesw as also provedt ob ee ffective for bifunctional oxygen electrocatalysis.…”